The son made the allegations during his eight day giving evidence at the Central Criminal Court. He also told the jury his father owned a rocket launcher, machine guns and a gun similar to one in a James Bond film.

He has previously alleged his father raped him, sexually abused him with a hot poker and forced him to have sex with his mother over the course of several years from when he was about six years old.

The father is alleged to have filmed some of these incidents and shown them to others. He is further alleged to have held a gun to the child's head and to have left him locked in a box.

The parents face a total of 82 charges of abuse between 2007 and 2011 in Waterford. The father and mother have pleaded not guilty to 16 counts each of sexual exploitation and one charge each of child cruelty. The mother has also denied 16 counts of sexual assault while the father denies 16 counts of anal rape and 16 counts of sexual assault with a poker.

Today the now 12 year old child told his father's barrister, Colman Cody SC, that he loved his mother and he missed her after being taken into care when he was eight years old.

He repeated allegations that his father forced him to “have sex” with his mother while he watched. He said his mother only participated “because she didn't want to go homeless.” He added his father threatened his mother that she would “have to go live on the streets” if she didn't comply.

Mr Cody put it to the child that he had said in a previous statement that his mother was happy to be having sex with the boy and that she threatened to kill him if he didn't take part.

The boy responded that this statement must have been written down wrong and that what he meant was his father threatened to kill him if he didn't take part.

Mr Cody asked the child about allegations, made last week, of his father filming this sex and showing it to visitors to the house. Counsel asked why he hadn't mentioned this during the garda statement. The boy insisted that he had.

Counsel put it to the boy that he first made allegations to his foster mother about being locked in a box by his father after watching a film about a gorilla who was kept in a cage. The child agreed with this.

The boy said he couldn't remember if he first made allegations about his father putting a “machine gun” to his head after watching a James Bond film.

He said he also couldn't remember if his foster mother would buy him a treat or toy every time he made an allegation against his father.

Counsel for the boy's mother, John O'Kelly SC, asked him to elaborate on details about his father's alleged firearms collection. The boy said his father owned “50 guns and 50 bullets” which included a rocket launcher, AK47, an Uzi sub-machine gun, “a sniper”, “a gun you can put a silencer on”, and a Beretta “like you would see in Dr. No in James Bond.”

He said his father also owned an 18th century ceremonial sword and several knives. He has previously said, when explaining why the guns weren't found by gardaí, that his father disposed of them the night before.

Mr O'Kelly put it to the child that “the sex with your mother didn't actually happen”. The boy responded that “everything I said did happen.”

The trial continues in evidence on Monday before Mr Justice Robert Eagar and a jury.